Many types of ligand-receptor assays have been used to detect the presence of various substances in body fluids, such as urine, saliva, or blood. Some commercially available assays are designed to make a quantitative determination, but in many circumstances all that is required is a qualitative positive/negative indication. Examples of such qualitative assays include blood typing, pregnancy testing, and many types of urinalysis.
U.S. Pat. No. 6,485,982, which is incorporated herein by reference in its entirety, describes a diagnostic test cell or device formed of an elongated outer casing which houses an interior permeable material (such as glass fiber) capable of transporting an aqueous solution by capillary action, wicking, or simple wetting. The casing defines a sample inlet, and interior regions, which are designated as a test volume and a reservoir volume. The reservoir volume is disposed in a section of the test cell spaced apart from the inlet and is filled with sorbent material. The reservoir acts to receive a fluid sample transported along a flow path defined by the permeable material and extending from the inlet and through the test volume. In the test volume is a test site comprising a first protein having a binding site specific to a first epitope of the ligand immobilized in fluid communication with the flow path (e.g., bound to the permeable material or to latex particles entrapped in or bonded to the permeable material). A window, such as a hole or transparent section of the casing, permits observations of the test site through the casing wall. The use of the test cell requires a conjugate comprising a second protein bound to colored particles, such as a metal sol or colloid, preferably gold. The conjugate can take two distinct forms, depending on whether the assay is designed to exploit the “sandwich” or “competitive” technique.
U.S. Pat. No. 7,045,342, which is incorporated herein by reference in its entirety, describes a diagnostic test device including a biphasic chromatographic medium. The biphasic substrate is formed of a release medium joined to a capture medium located downstream of the release medium. The release and capture media preferably comprise two different materials, or phases, having different specific characteristics. The two phases are joined together to form a single fluid path such that a solvent front can travel unimpeded from the proximal (upstream) end of the release medium to the distal (downstream) end of the capture medium.
For tests such as those described above, visually observable indicia can be preferred. Such indicia typically have included the presence of agglutination or a color change at a defined site on the assay. More recent efforts have included providing electronic (i.e., digital) signals as the observable indicia. For example, U.S. Pat. No. 7,763,454, which is incorporated herein by reference in its entirety, describes an electronic analyte assaying device that includes an electronic processing system and a liquid crystal display (LCD). The device includes a chromatographic medium and utilizes electronic components for evaluation of the test as well as display of the test results. Nevertheless, user interface with diagnostic test devices remain limited.
In particular, known point of care or over the counter diagnostic test devices lack an ergonomically favorable structure. As such, it is often difficult for a user to handle the device during application of the test fluid, such as from a urine stream, which can lead to either insufficient fluid application or device flooding. Because of these and other reasons, it would be beneficial to provide a personal use test device with improved ergonomic structure for ease of grip and use.